The purpose of the proposal is to modify and test research instruments which can be used to effectively screen samples of North American Indians and non-Indians age 65 years and over in a community survey in Manitoba, Canada, for dementia and also to determine differential diagnosis of the dementing disorders, particularly Alzheimer's Disease. Data to be collected will allow for the development of a screening algorithm for dementia and hopefully also for Alzheimer's Disease. This will be accomplished by means of a four stage design where Stage I involves the translation of the screening instrument and the establishment of cut-off points for Indians and non-Indians by administering the instruments to groups of known demented and non-demented subjects. Stage II involves the community survey by specially trained field workers. Stage III involves a comprehensive psychiatric and neurological evaluation of both cases and a sampling of non-cases identified from the community survey for clinical diagnosis and Stage IV involves the development of the screening algorithm from these data. The study will be conducted in Winnipeg with a sample of non- Indians (n=200) and in two Indian locations for a total of 205 Indians. This proposal is a resubmission of a previous application to undertake a comparative study of the prevalence of dementing disorders in these populations. The proposal has been substantially altered to address methodological issues which arose from the grant review. The solution of these methodological problems would be pertinent not only for the eventual completion of the original prevalence study but also for similar epidemiological studies involving geographically isolated, culturally distinct populations elsewhere in the world.